Freezer for Off Grid PV

[Naptown]

is it possible to make a fridge and freezer if you have the compressor. in the philippines everyting is expensive and I was wanting to go on a mainly 12vdc system to make the required box etc with a lot more insulation than a typical store bought unit would have might be more beneficial as long on you have the appropreiate space any idea's ie what kind of compressor etc I hear there are some of the new compressors that are extremely efficient an take a lot less load to kick them into gear in order to do the job
thoughts please

Yes this is done on boats all the time.
Look at marine refrigeration preferrably with hold over plates so it only has to run during the daytime.

[pakman]

make a fridge freezer

is it possible to make a fridge and freezer if you have the compressor. in the philippines everyting is expensive and I was wanting to go on a mainly 12vdc system to make the required box etc with a lot more insulation than a typical store bought unit would have might be more beneficial as long on you have the appropreiate space any idea's ie what kind of compressor etc I hear there are some of the new compressors that are extremely efficient an take a lot less load to kick them into gear in order to do the job
thoughts please

[brofig]

Like your original post

Pete;

I don't know about numbers...
but your ideas to save energy with the two chest type freezers makes sense to me.
thanks for sharing..

Brofig

[BritishPete]

120V AC (MSW). My freezer is presently the only Energy star qualified 5cu ft on the popular market and cost only $162 from Walmart. I have two identical one as fridge and one as freezer.

[Mike90250]

...PLEASE! Back to freezers now.

So, are you using a 120VAC for the freezer, or 12VDC ? Check out the home style energy star freezers, and see what their daily/annual power consumption is.

To get better cooling - insure the coils / hot side have pleanty of cooling air flow, don't put hot product into the freezer... you nkow the whole drill.

Insulation, can you add some externally ? Oftne the small, micro stuff has very low quality insulation.

[BritishPete]

You are dreaming. To use 1 Kwh per day at 12 volts requires a 440 AH battery every few years. I really do not care if you believe me or not because in a very short time you will learn that the hard way. A good 5 year 12 volt 440 AH battery will cost you $600 to $800

Once again READ my post. Did I ever say the 7 kwhr was coming out of the battery? Most of my power is used during insolation time. Your numbers tally almost exactly with mine; I use 2 Kwhr per day battery and I have 1000AH.


PLEASE! Back to freezers now.

[Sunking]

utility bill now it's FREE (or $60 every 5 years to keep you happy)

You are dreaming. To use 1 Kwh per day at 12 volts requires a 440 AH battery every few years. I really do not care if you believe me or not because in a very short time you will learn that the hard way. A good 5 year 12 volt 440 AH battery will cost you $600 to $800

[BritishPete]

LOL! The freezer is not my ONLY load, I produce and need 7 Kwhr per day from my panels. That would be a lot of fuel and inefficient use of my RV motor. However the topic is FREEZERS and saving battery power.

I could also (more cheaply) use my generator but at a far greater cost than my expected battery replacement costs.

So I joined an Off Grid forum today to talk about the BENEFITS of Off Grid. I gave up a 7 acre farm and a $600 a month utility bill now it's FREE (or $60 every 5 years to keep you happy)

Actually I have 12 Kwhr total of Trojan T105RE battery at a cost of $900 and a life expectancy of 8 years to my 30% discharge so $110 per year for all. Stll beats the heck out of Utility.

[Sunking]

Maybe you should re-read my post to see why it would cost $720; METER RENTAL !!! $12 per month.

Oops my bad, it is an RV. That being the case you do not need any solar, just a battery isolator using the alternator. Run the engine 5 minutes per day and you are done. Or you can do the solar thing if you do not like your money.

[BritishPete]

Anyway back to the real world; Anybody have any serious questions regarding my post on reducing freezer battery load? I also want to sell 125AH batteries at $350 LOL! I'd be rich in no time or you could try Trojan 105RE's 1.5Kwhr for $150. and 8 year life with my 30%DOD (that's 30% discharge) and 80% efficiency

[BritishPete]

If your job is using numbers I am sorry for you. I know PRACTICALLY what I use and how much it cost me. Sounds as if this is a customer sales pitch to me.

Maybe you should re-read my post to see why it would cost $720; METER RENTAL !!! $12 per month.

[Sunking]

Is that numbers too?

They sure are, but they are Make Believe. You di dno tuse correct math and formulas in any of your calculations.

In addition you did not account for battery system efficiency of 50%, used Average Insolation, and not given any allowance for cloudy day recovery.

With a battery system you have to generate 2 watt hours for every 1 watt hour used.
For a battery system you have to use December/January Insolation, otherwise you go dark in winter. In central Florida you get 3.8 Sun Hours.

So to generate 300 wh you need a panel wattage of [300 wh x 2] / 3.8 Sun hours = 150 watts. Round up 20% for cloudy day recovery = 180 watts. Pay attention here because this is where you really screwed up the math. To find the correct panel wattage the formula is [ Watt Hours x 2] / Sun Hours + 20% = Panel Wattage.

So you need:

180 watt solar panel = $1.79/watt x 180 watts = $320
15 Amp Charge Controller = $100
12 Volt 125 AH Battery = $350
500 watt True Sine Wave Inverter = $100
Est Total = $870

So you are getting off cheap living in Florida.

Total less than $200 compared to TECO $720.

Who the heck is TECO? At 12-cents/Kwh using 300 watt hours/day for 5 years = .3 Kwh/day x $.12/Kwh x 1825 days = $65.70

At $720 from TECO the Kwh cost would have to be $720 / 547 Kwh = $1.316/Kwh.

$720 for 547 Kwh. LOL.

[BritishPete]

Panel cost $1.79 per watt, average insolation (In Florida) 6 hours per day = 6 watt hours per $1.79. 300 watts therefore = $89 purchase price, 40A PWM controller $45, batteries existing anyway but would cost $100 per Kwhr to replace so $60 for 300 watts (to 50%DOD and your 5 years)

Total less than $200 compared to TECO $720 for the first 5 years and $60 per subsequent 5 years while TECO will still be $720.

Is that numbers too?

[BritishPete]

Follow me with a power supply LOL! WOW! What are you doing on an Off Grid Site? and how could you possibly know the life of my battery bank without knowing type of battery and DOD

Plus in my math 5 years at $12 a month equals $720. What do you know I don't?

I work with numbers too but from the PRACTICAL side, 0.3Kwhr per day cost me less than $100 in panels, where are you buying yours from?

[Sunking]

Not sure how you figure that; Mine is FREE. How much is 1/10 of free?

Simple I work with numbers, not feelings and emotions. As pointed out buying the electricity will cost you about a $1/month.


So you need about .3Kwh per day right? That will cost you about $1200 for the panels, charge controller, and battery. That does not include any misc materials and hardware. Of that $1200 the batteries will cost you around $350, and need replaced in 5 years or less.

So for the first 5 years:

If buying from the POCO will cost you .3 Kwh x $0.12/Kwh x 1825 days = $65.70
If you go the solar route about $1200.

So just how do you figure it is free?

My guess is because you feel that way.